Question

when primary key constraint is applied on one or more columns then it is known as ------------
1) foregin key
2) composite foregin key
30 composite primary key

Answer 1

Answer:

Option:3) composite primary key.

Answer 2

3) composite primary key is the correct answer.

Explanation:

• When a number one key constraint is carried out to 1 or extra columns then it's miles called a Primary key or Composite Key.
• Primary keys need to incorporate specific values. A primary key column doesn't have NULL values.
• A desk will have the best one number one key, which may also encompass unmarried or a couple of fields. When a couple of fields are used as a number one key, they're referred to as composite keys.

A composite key's made through the mixture of extra columns in a desk that may be used to uniquely pick out every row in the table while the columns are the blended specialty of a row is guaranteed.

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